information_theory.theory.txt

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                                  ┃   INFORMATION THEORY   ┃
                                  ┗━━━━━━━━━━━━━━━━━━━━━━━━┛

MESSAGE ==>                       #Message vs signal:
                                  #  - sent message is before encoding
                                  #  - sent signal is after encoding
                                  #  - received signal is before decoding
                                  #  - received message is after decoding

CHANNEL ==>                       #Way of communicating information from a source to a destination
                                  #Can have noise, i.e. modify signals
                                  #A channel has a unit (e.g. the bit)

PROCESSING ==>                    #Data encoding is translating a signal from one channel to another
                                  #Other possible processing:
                                  #  - FEC (forward error correction) channel coding: reduce impact of noise
                                  #  - compression / source coding: reduce size
                                  #  - cryptography: message confidentiality, integrity, authenticity
                                  #  - steganography: channel confidentiality

ENTROPY ==>                       #Information quantity.
                                  #Message meaning does not matter.

HAMMING DISTANCE ==>              #Number of different symbols (depending on units, e.g. characters) between two strings.

HAMMING WEIGHT ==>                #Hamming distance between a string and a null string (i.e. filled with null symbols,
                                  #e.g. 0 in binary)

LEVENSHTEIN DISTANCE ==>          #Number of single-symbol modifications (insertion, deletion or substitution) to do to go from
                                  #one string to another.